The present application relates generally to telephone systems and specifically to telephone systems that provide for real-time text captioning for the hard of hearing.
Modem telecommunication services provide features to assist those who are deaf or hard of hearing. One such feature is the text telephone (TTY) also known as a telecommunication device for the deaf (TDD). TDDs allow for text communication through the telephone system by generating tones that may be transmitted by analog telephone lines in response to a user typing letters on a keyboard.
Hearing users may communicate with deaf users who have TDD devices through so-called “relays.” A relay is a service funded by telephone communication surcharges that provides a “call assistant” who intermediates between a deaf user and a hearing user. The call assistant communicates with the deaf user using a TDD and communicates with the hearing user by voice over a standard telephone line.
A relay service may also be used to help those who are not deaf, but hard of hearing, by providing a captioned telephone. With a captioned telephone, a user who is hard of hearing may carry on a normal telephone conversation with a hearing user while a text transcription of the words spoken by the hearing user is displayed on the telephone. The text transcription allows the hard of hearing user to confirm his or her understanding of the spoken words. Unlike with a conventional relay service, captioned telephone requires extremely fast text transcription using a computer executed voice recognition system (typically with revoicing by a trained operator) so that the text captioning is as nearly as possible contemporaneous with the spoken words.
Text captioned telephones of this type are marketed under the service mark CAPTEL and described in U.S. Pat. Nos. 6,307,921 and 6,075,842 assigned to the assignee of the present invention and hereby incorporated by reference.
A text captioned telephone system employs a relay service in a mode where the relay transmits both the voice of the hearing user and a text stream of the spoken words by that user. A telephone of the receiving hard of hearing user provides a text display for displaying the captions.
In a single-line text captioned telephone, text and voice signals may be received over a single telephone line and separated electronically. The text captioned telephone includes software that automatically dials the relay, and providing the relay with the telephone number of the ultimate destination of the call. For incoming telephone calls, the hard of hearing user must normally hang up and redial the caller through the relay.
In a two-line text captioned telephone, a first telephone line communicates with the caller, and a second telephone line communicates exclusively with the relay. The two-line system allows text captioning to be easily used on incoming calls by allowing the text captioned telephone to dial out to the relay when the call is received and forward the necessary voice signal.
Many users of text-captioned telephony have jobs requiring significant use of the telephone as made possible by text-captioning. These users face a significant problem when they need to make use of telephone systems outside of their normal work environment where text captioning telephones may not be available or equipment such as cellular telephones that does not support text captioning must be used. Many workplaces use proprietary private branch exchange (PBX) telephone lines that do not support analog text captioning telephones, the latter which require standard telephone connections.